Medical/biological study (experimental study)

Rodent cell transformation and immediate early gene expression following 60-Hz magnetic field exposure med./bio.

By: Balcer-Kubiczek EK, Zhang XF, Harrison GH, McCready WA, Shi ZM, Han LH, Abraham JM, Ampey 3rd LL, Meltzer SJ, Jacobs MC, Davis CC

Published in: Environ Health Perspect 1996; 104 (11): 1188-1198

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Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 10 , 20 and 40 min	magnetic flux density: 5.7 µT minimum (unspecified) magnetic flux density: 57 µT magnetic flux density: 570 µT maximum
Exposure 2: 60 Hz Exposure duration: continuous for 24 h	magnetic flux density: 200 µT unspecified (unspecified)

General information

1.5 Gy of X-ray was used to elicit a positive transformation response in SHE or CH3/10T1/2 cells and as negative control for c-fos expression in HL60 cells. Hyperthermia at 45.5°C for 9 min and TPA at 0.3 µg/ml for 30 min or 50 ng/ml for 3 h were used as treatments modifying the expression of c-myc, c-fos and ODC.

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	continuous for 10 , 20 and 40 min
Additional info	HL60 cells were exposed. Reference Article: Little JB, Nagasawa H, Kennedy AR. DNA repair and malignant transformation : effect of X radiation , 12-O-tetradecanoyl-phorbol-13-acetate, and protease inhibitors on transformation and sister-chromatid exchanges in mause 10 T1/2 cells.

Exposure setup

Exposure source	solenoid
Chamber	water bath insulated with styrofoam ( 1.2 m long, 0.7 m wide, 11 cm deep) maintained at 37°C.
Setup	solenoids, 38.7 cm long, 12 cm in diameter, 199 turns; tissue culture flasks were placed horizontally in the central planes of long solenoids wound on thin-walled plexiglas cylinders enclosed in magnetic shield cylinders (22.9 cm in diameter), all of them were placed parallel to each other in water bath; cells were parallel to the field lines which was uniform along the 18 cm long central plane.
Sham exposure	A sham exposure was conducted.
Additional info	Control cells experienced zero magnetic field but were subjected to the same level of disturbance such as local acoustic noise and convective heating.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	5.7 µT	minimum	measured	unspecified	-
magnetic flux density	57 µT	-	-	-	-
magnetic flux density	570 µT	maximum	-	-	-

Measurement and calculation details

MF measurements were made with a three axis detector and were verified before each experiment using a small field sensor.

Exposure 2

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	continuous for 24 h
Additional info	C3H/10T1/2 cells and SHE cells were exposed

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	200 µT	unspecified	measured	unspecified	-

Exposed system:

intact cell/cell culture
C3H 10T1/2 cells (derived from mouse embryo fibroblasts), Syrian hamster embryo cells (SHE) and HL-60 (human acute myeloid leukaemia cells)

Methods Endpoint/measurement parameters/methodology

cell transformation: neoplastic transformation (transformation frequency, morphological colony criteria, null method)
molecular biosynthesis: ornithine decarboxylase (ODC), c-myc, ß-actin, GAPDH, ribosomal (18S, 28S) gene expression (Northern blot)
cell viability/cell division/proliferation: cell survival (plating efficiency)

Investigated system:

Time of investigation:

after exposure

Main outcome of study (acc. to author)

No transformed colonies were found in SHE cells exposed to 60 Hz magnetic fields.
There were no significant differences in plating efficiency among exposed and sham exposed C3H 10T1/2 cells. Incubation in TPA enhanced the transformation induced by 1.5 Gy gamma rays radiation. TPA incubation in exposed and sham exposed cells alone had no effect.
Exposure to 60 Hz magnetic fields had no effect on ornithine decarboxylase gene expression whereas treatment with TPA increased ornithine decarboxylase transcription level in exposed and sham exposed SHE cells.
No statistically significant effects were observed in gene expression in HL-60 cells exposed to 60 Hz magnetic fields.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA
Public Health Service (PHS), USA
University of Maryland, USA

Lee HJ et al. (2012): Combined effects of 60 Hz electromagnetic field exposure with various stress factors on cellular transformation in NIH3T3 cells
Czyz J et al. (2004): Non-thermal effects of power-line magnetic fields (50 Hz) on gene expression levels of pluripotent embryonic stem cells-the role of tumour suppressor p53
Jin M et al. (2000): ERK1/2 phosphorylation, induced by electromagnetic fields, diminishes during neoplastic transformation
Balcer-Kubiczek EK et al. (2000): Expression analysis of human HL60 cells exposed to 60 Hz square- or sine-wave magnetic fields
Morehouse CA et al. (2000): Exposure of Daudi cells to low-frequency magnetic fields does not elevate MYC steady-state mRNA levels
Miyakoshi J et al. (2000): Exposure to extremely low frequency magnetic fields suppresses x-ray-induced transformation in mouse C3H10T1/2 cells
Loberg LI et al. (1999): Gene expression in human breast epithelial cells exposed to 60 Hz magnetic fields
Gamble SC et al. (1999): Syrian hamster dermal cell immortalization is not enhanced by power line frequency electromagnetic field exposure
Tipping DR et al. (1999): Observations on the effects of low frequency electromagnetic fields on cellular transcription in Drosophila larvae reared in field-free conditions
Jahreis GP et al. (1998): Absence of 60-Hz, 0.1-mT magnetic field-induced changes in oncogene transcription rates or levels in CEM-CM3 cells
Owen RD (1998): MYC mRNA abundance is unchanged in subcultures of HL60 cells exposed to power-line frequency magnetic fields
Balcer-Kubiczek EK et al. (1998): BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields
Miyakoshi J et al. (1998): Enhanced NOR-1 gene expression by exposure of Chinese hamster cells to high-density 50 Hz magnetic fields
Harrison GH et al. (1997): Kinetics of gene expression following exposure to 60 Hz, 2 mT magnetic fields in three human cell lines
Jin M et al. (1997): Biological and technical variables in myc expression in HL60 cells exposed to 60 Hz electromagnetic fields
Miyakoshi J et al. (1996): Exposure to magnetic field (5 mT at 60 Hz) does not affect cell growth and c-myc gene expression
Lin H et al. (1996): Electromagnetic field stimulation of biosynthesis: changes in c-myc transcript levels during continuous and intermittent exposures
Desjobert H et al. (1995): Effects of 50 Hz magnetic fields on c-myc transcript levels in nonsynchronized and synchronized human cells
Lacy-Hulbert A et al. (1995): No effect of 60 Hz electromagnetic fields on MYC or beta-actin expression in human leukemic cells
Saffer JD et al. (1995): Short exposures to 60 Hz magnetic fields do not alter MYC expression in HL60 or Daudi cells
Lin H et al. (1995): Electric and magnetic noise blocks the 60 Hz magnetic field enhancement of steady state c-myc transcript levels in human leukemia cells
Lin H et al. (1994): Specific region of the c-myc promoter is responsive to electric and magnetic fields
Gold S et al. (1994): Exposure of simian virus-40-transformed human cells to magnetic fields results in increased levels of T-antigen mRNA and protein
Cain CD et al. (1993): 60 Hz magnetic field acts as co-promoter in focus formation of C3H/10T1/2 cells
Goodman R et al. (1992): Exposure to electric and magnetic (EM) fields increases transcripts in HL-60 cells: does adaptation to EM fields occur?
Goodman R et al. (1992): Exposure of human cells to electromagnetic fields: effect of time and field strength on transcript levels

Rodent cell transformation and immediate early gene expression following 60-Hz magnetic field exposure med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

General information

Exposure 1

Main characteristics

Exposure setup

Parameters

Measurement and calculation details

Exposure 2

Main characteristics

Exposure setup

Parameters

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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